342 NOTES ON BRITISH FOREST TREES. 



l)laiiks in existing woods. It is treated under a rotation of 10 

 to ()0 3'ears in high forest, and of 15 to 20 years as coppice ; 

 for the production of withes it may be cut over after 3 to a 

 years, according to circumstances. 



Ii. Formation of 'Wtmls. 



They can be formed artificially or naturally. The seed 

 ripens from the end of August to October, according to 

 locality, and commences falling soon afterwards up to 

 February. It maintains its germinating power for (5 to 

 12 montiis. It is considered good seed if 20 per cent, of 

 it germinate. One pound of clean seed contains something 

 like 800,000 seeds. 



Direct sowing is rarely done. Broadcast sowings would 

 require about 30 pounds of seed per acre, which should be 

 very thinly covered, only about one-eighth of an inch. The 

 seed germinates after 2 to 3 weeks. Seed which has ripened 

 early in the autumn may germinate in the same year : other- 

 wise it lies dormant till spring. 



In nurseries the seed is sown broadcast and covered by 

 sprinkling a little earth over it. The one year old seedlings 

 may be pricked out and left for one or two years in the 

 nursery lines, according to requirements. On the Continent 

 one or two year old plants are used for planting. 



Birch can easily be regenerated naturally under a very 

 small number of mother trees. Generally it appears wherever 

 it has a chance of springing up, and the forester has more to 

 fight against it than to favour it. 



/. Tr)iillii;l. 



Fcrtilit/i of .S'o/7.— Eaily opening out and a thin crown do 

 not enable the birch to act beneficially upon the soil ; hence 

 it should not be grown pure, except on localities where more 

 valuable trees will not thrive. 



KxtcDud Danfji'i-H. — Birch, being very hardy, requires no 

 tending against climatic infiuences : the damage done by snow, 



